The information traditional instruments will give you is comparable in accuracy to electronic instruments, though electronic instruments have very important advantages.
The expression "traditional" is perhaps now misleading, since the electronic instruments have now more or less become the standard for use in most countries. The chemical and mechanical analysers have, fortunately, become the exception to the rule.
For example, contrary to traditional instruments, flue gas analysers monitor on a continuous basis. That ensures you that you will not oversee the most important value, because you can follow the changes automatically and rapidly, and provide a printout of the measured and stored data, and furthermore you have the opportunity to transfer the data to a computer. Stack testing is no longer a game. It is carried out for a number of legal and financial reasons. Satisfying local regulations is an important factor in the continued existence of a company, and nobody will take such matters lightly. The chemical methods leave many factors out of the equation, such as cross-sensitivity effects and transient changes. Since the regulatory authorities are almost all equipped with electronic instruments that will take all these factors into account, there is little advantage in remaining with the ancient methods. In the long run, these are more expensive, since the chemicals must be bought and stored. These are often classified as dangerous liquids for very good reasons and will require the operators to use protective equipent when handling them as well as posing serious storage problems.
Flue gas analysers have also been reduced dramatically in size from the old type of cased instrument weighing around 20 kg to an instrument that can truly be designated a hand held analyser. Weighing less than one kilogram in most cases they are powerful and less expensive relatively than they ever were. The flue gas analyser has really ceased to be an expensive laboratory instrument and is now a medium priced field instrument, in use on building sites and on the factory floor. Laboratory style flue gas analysers do still exist, of course, but they are more used for experimental work or as standard for comparison to other flue gas analyzers.
Overall, electronic flue gas analysers have many important advantages, such as ease of use and speed, automatic sampling, calculations and report generation. The ability to connect them to a computer and download stored results has made their use much quicker and simpler. Most common flue gas analysers have enough memory capacity to store the results from a day's work, which can then be collected in one package afterwards, complete with comments and date/time etc. Cordless communication is here also coming into use. A Bluetooth connection can easily be applied to an existing interface enabling wireless communication with a range of different instruments.